Biomaterials
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Although surgery techniques improved over the years, the clinical results of peripheral nerve repair remain unsatisfactory. In the present study, we compare the results of a collagen nerve guide conduit to the standard clinical procedure of nerve autografting to promote repair of transected peripheral nerves. We assessed behavioral and functional sensori-motor recovery in a rat model of peroneal nerve transection. ⋯ We observed that 1) the locomotor recovery pattern, analyzed with kinetic parameters and peroneal functional index, was superior in the GS and CT groups; 2) a muscle contraction was obtained in all groups after stimulation of the proximal nerve but the mechanical muscle properties (twitch and tetanus threshold) parameters indicated a fast to slow fiber transition in all operated groups; 3) the muscular atrophy was greater in animals from TM group; 4) the metabosensitive afferent responses to electrically induced fatigue and to two chemical agents (KCl and lactic acid) was altered in GS, CT and TM groups; 5) the empty collagen tube supported motor axonal regeneration. Altogether, these data indicate that motor axonal regeneration and locomotor recovery can be obtained with the insertion of the collagen tube RevolNerv. Future studies may include engineered conduits that mimic as closely as possible the internal organization of uninjured nerve.
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Reconstructed human skin equivalents (HSEs) are representative models of human skin and widely used for research purposes and clinical applications. Traditional methods to generate HSEs are based on the seeding of human keratinocytes onto three-dimensional human fibroblast-populated non-human collagen matrices. Current HSEs have a limited lifespan of approximately 8 weeks, rendering them unsuitable for long-term studies. ⋯ The presence of hemidesmosomes and anchoring fibrils was demonstrated by electron microscopy. Finally, we show that the presented HSE contained a higher concentration of the normal moisturizing factor compared to rat-tail collagen-based skin models, providing a further representation of functional normal human skin in vitro. This study, therefore, demonstrates the role of the dermal microenvironment on epidermal regeneration and lifespan in vitro.
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Hemorrhage remains a leading cause of early death after trauma, and infectious complications in combat wounds continue to challenge caregivers. Although chitosan dressings have been developed to address these problems, they are not always effective in controlling bleeding or killing bacteria. We aimed to refine the chitosan dressing by incorporating a procoagulant (polyphosphate) and an antimicrobial (silver). ⋯ The silver dressing also significantly reduced mortality from 90% to 14.3% in a P. aeruginosa wound infection model in mice. Although the dressing exerted severe cytotoxicity against cultured fibroblasts, wound healing was not inhibited. This study demonstrated for the first time, the application of polyphosphate as a hemostatic adjuvant, and developed a new chitosan-based composite with potent hemostatic and antimicrobial properties.
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The treatment of massive full-thickness burns with engineered skin substitutes has shown promise in clinical trials. The majority of skin substitutes are comprised of fibroblasts and/or keratinocytes on collagen scaffolds, commonly generated by freeze drying which can generate significant structural heterogeneity. Electrospinning may generate collagen scaffolds with greater homogeneity. ⋯ At 8 weeks post-grafting, the ECSS grafts were 61.3+/-7.9% original graft area whereas the FCSS grafts were 39.2+/-8.8% original area (p<0.01). These results indicate that ES scaffolds can be used to fabricate skin substitutes with optimal cellular organization and can potentially reduce wound contraction compared to FD scaffolds. These advantages may lead to reduced morbidity in patients treated with skin substitutes fabricated from ES collagen.
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The peer-review process remains a central part of the value and validity of scientific and technical publishing and proposal assessment. The peer review mechanism has many delicate components that should function most professionally and effectively for best results. ⋯ An additional component involves follow-on policing of published literature to assert its validity through consensus and validation. This short essay examines our collective duties as contributors, reviewers, and readers to the integrity and safekeeping of this essential quality control process.